LOS ANGELES – Google Photos, which launched in May, has made a huge impact in its short life, attracting upwards of 100 million people to download the app and use the Web service.

Rolling out for Android, iOS, and the Web, Google Photos now lets groups pool their collective snapshots and videos to create shared compendiums of memories, be it for your gran’s 80th birthday, a graduation, or a drunken night out.When Google rolled out with its Photos app this past May, over a hundred million users embraced the idea of sharing images and albums by sending links via text message, email or messaging apps. Google Photos today launched “Shared Albums,” a way to privately get photos to loved ones and friends, and in turn, have them grow the album with additional photos. Google announced the change today, and it’s simple: you make an album on Google Photos, and you can choose to share it with anyone you want (whether that’s through a shareable link or an email invitation). David Lieb, the product lead for Google Photos, sees sharing photos this way as the antithesis to what’s become the “aspirational” photos seen on social media–upbeat, happy photos of parties, trips and other occasions.

Participants can download photos to their local devices, and anytime a photo is added to the album all participants will receive a notification about it. I chatted with the Google Photos Product Lead, David Lieb, about shared albums and the reason why they were such an important feature to get out into the wild…especially before the holidays. As Google’s video demonstration shows, one simply opens up the Photos app, selects all the images he or she wants to share and then clicks on new shared album. This effectively transforms the service from a simple photos dump to a slow-building social tool, and it should be a killer feature that’ll help drive adoption even further.

Leib sees a wedding album taking place online where the various guests of the party begin pooling their pictures together that they snapped at the ceremony and reception, and it grows and grows over time. For example, videos and animated photos will appear in your album as if the subjects are moving, an old feature carried over from Google Photos that will still make people smile. (Note: Oddly, this only works in the iOS version, but Google says this is eventually coming to Android.) Shared album images can be rearranged by the album owner, while Apple’s can’t be moved after they’re added. Album collaboration starts not by inviting others via email or phone number, like Apple’s, but by sending a simple link using whatever method you prefer.

The added feature also allows users to save photos and videos from shared albums to their Google Photos library, even if they weren’t the ones who originally snapped them. While the collaborative experience of shared albums sort of transforms Google Photos into its own social media network of family and friends, it’s severely missing the functions to make it a full-blown social media force. You’re taking photos of things you could buy for lunch, or asking people “should I buy this dress?” But if you look at where most of the photos we take sit on that spectrum, it’s somewhere in the middle of those two. Amazingly enough, you can’t caption, comment on, or like things that you share or see, and this sucks the emotion from albums, leaving you with an unsatisfying feeling.

Another drawback — depending on your preference — is Photos arranges your images through shared albums in chronological order of when they were taken and not added, which is sure to irk some users. Google Photos impact on the photo sharing world was quite clear this week when Dropbox said it would dump its Carousel photo sharing feature in 2016 Several analysts said it made no sense for consumers to pay for this feature and storage when Google Photos offers storage for free. To vie for your attention on iOS, it would help if Google’s app intelligently integrated into the operating system, using things like richer notifications. And Google’s version of shared photos has to be easy enough for everyone to use — including great-grandparents who are itching to see new shared photos of their kids’ kids’ kids. Lieb tells me the Photos team took special care to make sure the feature was as simple to use as possible, or nobody would ever use it: One of the more popular set of features in Google Photos is everything that happens within the “Assistant” tab.

Imagine sharing a few photos, your friends and family do the same and then boom…you have a killer collage or animation from many different perspectives. He said he prefers to figure out when and where to allow comments and likes, for example, creating a space where comments are left on the entire album, rather than on each photo.

It most certainly is doable, and when you think about the possibilities for video, Google’s latest acquisition FlyLabs could become very handy for all of this. Lock screen notifications for Google’s shared albums are text-only because Apple’s ecosystem still only lets Apple’s apps use the tiny thumbnail that appears beside a notification. Apple users aren’t likely to switch to it any time soon, but if shared albums fixes its problems, it could be a big win for Android and people who use both platforms.